I started looking at this because I was wondering if we really needed the complexity of the 'deleteRegion' argument to _run_openstack_cmd.

I think that this is an unnecessary optimization. We can keep the region configuration in EOS even if there is nothing running in it (at least we can see that it exists from EOS). This would let us get rid of the deleteRegion option to _run_openstack_cmd, which will help clean up that method imho.